12 EC300 frame "reliefs"

[Front Royalty]

Maybe I missed another thread about this, but...

Anyone else notice how the frame is ground and cut to accommodate the intake boot and shock reservoir? I'm very concerned about this. Anything to be worried about? Is this something they have been doing with success? Having a mechanical background, I can't imagine this is the proper way to do things!

 

[nato]

Yeah it will be fine mate mine is holding up no worries.

 

[Front Royalty]

I sure hope so! The structural integrity of the frame is compromised greatly at both points. Hopefully they will replace my frame when it breaks!

 

[twowheels]

Maybe I missed another thread about this, but...

Anyone else notice how the frame is ground and cut to accommodate the intake boot and shock reservoir? I'm very concerned about this. Anything to be worried about? Is this something they have been doing with success? Having a mechanical background, I can't imagine this is the proper way to do things!

Just be careful about not introducing stress risers at those points and you'll be fine. You may want to space the airboot off of the subframe with some split rubber tubing if it hasn't already been done, and check and see that the shock reservoir has adequate clearance to the relief on the right side.

 

[GMP]

I don't think this is an issue at all. Time better spent cleaning up other details. I bottomed (HARD once) landing from a couple doubles and its still in one piece. The old pre '03 frames had half the gussets and they were fine too. This is the least of my worries.

 

[Front Royalty]

Just be careful about not introducing stress risers at those points and you'll be fine. You may want to space the airboot off of the subframe with some split rubber tubing if it hasn't already been done, and check and see that the shock reservoir has adequate clearance to the relief on the right side.

Thanks. Guess we'll see!

 

[GasGas]

Thanks. Guess we'll see!

Isn't that a big hunk of cast steel? I think you would be hard pressed to break that.

 

[Front Royalty]

Isn't that a big hunk of cast steel? I think you would be hard pressed to break that.

Hold my beer and watch this!

 

[Cruiser]

Hold my beer and watch this!

Wait!! lemme get the video machine runnin first..

 

[noobi]

Im bored, so ive been thinking about this too much.
The most common 'frame' failure ive seen, is KTMs snapping the steering stem, lower clamp or steering tube. Which imo, is more likely than a complete frame failure. However, you can still find pictures of total frame failures, also of KTMs.

For arguments sake.
The point at which CrMo steel begins to yield is ~450MPa, 450000000 N/m^2.
Im just thinking up these areas based on looking. Lets say its 60mm at its thinnest section, and 3mm? thick giving an area of 0.00018m^2.
Lets assume the chassis is essentially rigid, a fairly safe assumption as that's how they are designed. Meaning that the relieved portion of frame can safely withstand up to 81000N of force, which is equivalent to ~8000kg, before starting to deform irreversibly.

8 tonne after the suspension has bottomed. Lets say you would have to try, and would probably have other problems.


This is assuming no shear, torque or bending and that there is no material defects and no effective stress concentration at the relieved parts.
I did say for arguments sake

 

[GMP]

The frame section was not just "cut out" after the fact, it was designed and cast that way. Considering all the holes in the section as well, I'm sure this was an area of focus. If you land or hit something hard enough to break this you will have much bigger problems! I'd say femur, back, subframe would go first.